Ventilation of a patient involves the delivery of a breathable gas (typically ambient air to which a complementary gas such as oxygen can be added) pressurised above atmospheric pressure to a patient via a conduit, and a mask or tracheotomy tube.
There are an increasing number of disorders that require assisted and/or controlled ventilation of the patient. It is namely common to use breathing assistance devices for diseases where mechanical ventilation is needed, for example in neuromuscular disease where volume controlled ventilation is required. These devices may also be used for other respiratory diseases or disorders, such as for providing continuous positive airway pressure treatment for obstructive sleep apnea.
For either application of assisted and/or controlled ventilation, the pressure of the gas delivered to patients can be constant level, bi-level (in synchronism with patient breathing) or auto-adjusting in level. This enables controlling the Positive Expiratory Pressure (PEP) to remain equal to the expiratory pressure of the patient, so that the residual overpressure in the patient lungs is balanced. Throughout this specification reference to gas supply unit is intended to incorporate a reference to any one of, or combinations of, these forms of pressurised gas supply.
It is desirable to minimize the size of the respiratory system for increasing the mobility and comfort of the patient. It is also sought to have a respiratory system which may be used in a variety of places and circumstances (e.g. home or hospital), and which therefore needs to be both simple and reliable.
It has thus been proposed to use a respiratory system including a gas supply unit connected to an electromagnetic gas regulating valve via a single gas conduit. Such valves are described in the PCT application published on Nov. 9, 2006 under the reference WO 2006/117379, which is incorporated herein by reference in its entirety. With such gas regulating valves, the gas supply unit of the respiratory system can be reduced in size, and a single gas conduit is needed which eases movement of the patient. However, such an electromagnetic valve is heavy which is not comfortable for the patient. This kind of valve is also quite expensive as it is made with uncommon elements and is quite complex to manufacture.
Therefore, it is an object of the present invention to provide a gas regulating valve that substantially overcomes or at least ameliorate one or more of the above deficiencies.